1. Technical Field
This disclosure relates to systems and methods for the inspection, modification and repair of surfaces, samples and microscopic devices in energetic-beam microscopes; in particular, for methods of inspection, modification and repair in focused ion-beam microscopes, scanning electron microscopes and similar instruments.
2. Background Art
Current repair and modification processes for integrated circuit chips (IC's) and for masks generally rely on the formation of local areas of energy dissipation on the surfaces thereof to cause locally confined endothermic reactions. These reactions allow for selective etching or deposition of materials. Focused beams of ions, electrons or photons are used to form these local areas. Focused ion-beam (FIB) tools have thus become dominant in most repair applications, as well as for specimen extraction for failure analysis of IC's.
New materials used in current generation IC's, such as copper and low-k dielectrics, or new materials in photo masks, are not compatible with conventional FIB processes because of damage to dielectrics or scattering of conductive byproducts. Imaging the chip surface with the focused ion beam during navigation to a repair site can also result in damage to the dielectric. Thus, other imaging methods must be used, such as electron beams or laser energy.
Further, typical FIB and SEM chambers have layouts that make it difficult to view the sample being processed, because such chambers generally cannot accommodate an optical microscope for directly viewing the sample. Difficulties with optical microscopes also arise because of the short working distances that may be required to achieve a reasonable numerical aperture (NA), and therefore the difficulty of illuminating the sample by off-axis illumination without shadowing by the objective lens. Also, the conventional optical microscope objective would block one or both of the charged-particle beams in the typical FIB chamber.
There is thus a need for a system and method for conveniently viewing a sample in the vacuum chamber at the same time as processing takes place, and without damaging the sample in viewing and navigation to a repair site. Further, it would be advantageous if a single optical channel could be used for both imaging and processing so as to reduce the size of the instrument in the small chambers of FIB's and SEM's. The use of a single channel for both imaging and processing would not only allow for viewing a process under way, but would also allow optical imaging to be combined with other techniques. An example, not heretofore practical, would be inducing optical fluorescence of nanoparticles in a biological sample with an electron beam, while illuminating the sample with laser light to induce Raman emission in a spectrum of interest.